Preparation and Performance Evaluation of Coated Tracer Sand for Segmental Fracturing of Horizontal Wells

Multistage fracturing technology for horizontal wells has become a core technology for the effective development of shale and other unconventional oil and gas resources. Following the fracturing and modification of horizontal wells, reliable monitoring of the fracturing effect of each interval, the return of drainage, and the fluid production profile during subsequent production is an important prerequisite for further optimization of the fracturing program and sustainable and effective development. The use of coated tracer sand allows the fracturing effect of horizontal good segments to be assessed and the fluid production profile of horizontal wells to be evaluated in real-time during production. This approach facilitates the improvement of the horizontal well development efficiency. This paper investigates a preparation method for slow-release-coated tracer sands and determines a reasonable preparation method by optimizing the proppant, coated components, and effective components of the tracer. The prepared samples are evaluated for performance parameters, including particle size, salinity, temperature, pH, and mud velocity. The results of this study indicate that the particle size and salinity of tracer particles with intact coated films have a minimal effect on slow-release performance. However, it was observed that the presence of acid enhances the release of slow-release particles, while alkalinity inhibits the release of coated particles. Higher temperature increases the release rate. If the conditions stay the same, then the slow release of coated particles follows a set speed law. But above a certain speed, the release rate and amount increase greatly. This study provides a theoretical basis for using coated slow-release tracer sands in monitoring horizontal well fracturing.